In a display skill field, a flat panel display possesses advantages of being ultra thin, power saved and radiation free. It has been widely utilized. A present flat panel display, such as a LCD (Liquid Crystal Display) or an OLED (Organic Light Emitting Display) has been gradually replacing the CRT displays. The OLED possesses many outstanding properties of self-illumination, low driving voltage, high luminescence efficiency, fast response, high clarity and contrast, near 180° view angle, wide range of working temperature, applicability of flexible display and large scale full color display. The OLED is considered as most potential flat panel display technology.
Generally, OLED comprises a substrate, ITO transparent anode located on the substrate, a Hole Injection Layer (HIL) located on the ITO transparent anode, a Hole Transporting Layer located on the Hole Injection Layer, an Emitting Material Layer (EML) located on the Hole Transporting Layer, an Electron Transport Layer (ETL) located on the emitting material layer and a Cathode located on the Electron Injection Layer. For promoting the efficiency, the emitting material layer is generally applied with co-host system. At present, the manufacture method of the OLED is forming film on the ITO anode layer with organic material by vacuum deposition. Then, the metal cathode is deposited thereon by vapor deposition or sputter.
OLED full color display is a major developing trend of OLED skill. The proposed OLED full color skill now comprises five types of RGB side by side, color conversion, color filter, micro-cavity and multilayer stack. The OLED full color skill utilizing the micro-cavity has merits of high luminescence efficiency, high color purity, applicability of large scale production and etc. By using the effect of micro-cavity, the lights of some specific wavelengths can be enhanced and other lights get weaken.
The characteristics of luminescence of the micro-cavity is decided by the optical length thereof and related with material thicknesses of each layers. Most of the present micro-cavities are flat firm structure. The luminous intensity and the color have strong directionalities and make against the achievement of wide view angle display.